You may, or may not, be aware that XBRL Formulas is a candidate recommendation. I have created a number of annotated XBRL Formulas samples which may be useful to business users who want to see how this stuff looks and works by looking at XBRL Formulas at the XML level (the angle brackets). There are five small but comprehendible taxonomies (sales analysis, movement analysis, directors compensation, etc) and one file which puts all the taxonomies together into one taxonomy. I organized the XML so it is easy to read and so it flows in a logical manner, to enable reverse engineering the linkbases. I also carefully named the XLink labels to help someone “walk” through the linkbases. Basically, look for the “*-formulas.xml” file in each subdirectory.
The taxonomies and instance documents validate against three different XBRL processors which support XBRL Formulas (and it is great that there are already three processors!). I did everything I could to get this right, but be warned that this stuff is rather new.
For these samples, see here. (The XBRL Formulas page on this blog.)
XBRL Formulas is critical. There are many computations which cannot be validated by XBRL calculations. XBRL calculations are very limited. The biggest limitation is that they only work if all the things you want to calculate are in the same context. For movement analysis (beginning balance, changes, ending balance...each of which is in a different context) and for cross dimensional computations (each dimension in a different context), calculations simply will not work.
Keep watching the XBRL Formulas page, more to come.